Pressed tube for tire valves



v jan. 20, E925 I L523532 T. P. CHAMBERS ffl@ latented dan. 20, 1%25.

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THOMAS PENTLND CHAMBERS, OF TORONTO, ONTARIO, CANADA.

PRESSED TUBE FOR TIRE VALVES.

Application mea December s, 1921. serial No. 520,397.

To all 'whom t may concern Be it known that I, THOMAS PENTLAND CHAMBERS, a subject of the King of Great Britain, and resident of th/e city of Toronto, in the Province cf Ontario and'Dominion of Canada, have invented certain new and useful Improvements in Pressed Tubes for Tire Valves, of which the following is a specication.

My invention relates to new and useful improvements in a process for making tubes for tire valves for automobiles and the like, as described inthe present specification, and referred to in the accompanying drawings that form part of the same.

My invention relates more particularly to the manufacture of valve stems for pressed tire valves and which consists essentially in extruding from a cylindrical billet, tire valve tubes by means of a thrust die comprising a tubular punch provided with a punch pin therein adapted to project below the punch into an aperture formed in the valve tube.

The objects of ,my invention are to provide a new, etcient and more economical method or process for making, in the shortest possible time, and with minimum expense, a pressed valve stem formed with a hole through the centre.

A further object is to save the time required under existing methods, for turning brass bar rods and then drilling a. hole through the centre, or the further time required for forging the stein on the end of the tube, and then drilling. rlhis turning and drilling is all done away with under my process, the stem with hole therethrough being formed with the tube on the end thereof in onefoperation. Moreover, in addition tothe time required for turning and drilling the stems at present, the output is limited to two valves to a pound of metal, while lwith -my process a valve output of eight valves to the pound is obtained.

With these and other objects in view, reference is now had to the accompanying drawings in which like numerals of reference. in-

. dicate corresponding. parts in each figure and in which:

Figure 1 is a vertical section of the die and punch assembly.

Figure 2 is a mandrel or punch pin.

Figure 3 is a vertical section of the valve tube.

Figure 4 is a vertical section of the billet.

Figures 5 and 6 are bottom plan views of Referring to the drawings:

10 is a cylindrical die holder provided with a thrust plate 11 secured thereto and therein at the base. 12 is a guide bushing mounted within the die holder 10 and supported on the thrust plate 11. 13 is the die bushing inserted within the, guide bushing 12. 14 is a tubular punch adapted to be inserted'within the guide bushing 12 having mounted therein the punch pin lvadapted to project below the punch die and into the bushing 13. The punch pin is here shown in Figure made smaller towards the outer end. It can, however, be made of uniform dimensions throughout, the narrow form of end being used only for economicalpurposes.

The mode of practising my invention is as follows:

The hot metal is first moulded to the re- 1 quired billet-shape (as shown in Figure 4) by suitable dies, then press-formed around the punch-pin 15 carried by the tubular punch 14, and, on the metal cooling and contracting, the punch-pin 15 is removed andthe valve tube with the integral hollow stem is completed except for the screw-thread on the outside.

As many changes could be made in the above construction and many widely di'erent embodiments of my invention within the scope of the claims, constructed without departing from the spirit or scope thereof, it is intended that all matter contained in lthe accompanying specification and drawings shall be interpreted as villustrative and not in a limiting sense.

What l claim s my invention is:

1. The method of forming tubular articles by extrusion of a die press, having a die holder, a thrust plate, a die with a reduced throat portion, and a guide bushing for centering the die, consisting of inserting a perforated billet in the guide bushing and on the die, inserting a tubular punch with a removable punch pin held therein in the guide bushing with the'lower end of the pin extendingthrough the billet, pressing the billet to form a tube by a single contact ing flow of the metal at the throat of the die by the action ofthe punch and punch pin being moved downward, stopping the pressing to leave a head on the tube, and moving the punch and punch pin upwards, the

direction and at the same speed in all operations.

2. An apparatus for die pressing tubes -by extrusion, comprising a flattopped, circular thrust plate having a central opening, a. cylindrical die holder supported and' centered by the thrust plate, a guide bushing inserted in the die holder and seated on the thrust plete, e die fitting the guide bushing and centered thereby, and seatedl on the thrust'plate9 seid die having a single throat portion or reduced diameter to form the tube by e, single contracting flow of metal, a tubular punch operating in the guide bushing,. a removable punch pin inserted therethrough and operating at the lower end and held he punch to operate therewith in the same direction and at the saine speed in all operations.

3. An apparatus for die pressing tubes by extrusion, comprising a thrust plate, with an aperture in the centre of larger diameter than the tube to be formed, having a circular periphery, a shoulder thereabout, and having a, hat upper surface, a cylindrical die holder fitting over the periphery of the meshes ai guide bushing inserted -Within the die holder and seated on the upper face ott the thrust plate, a die tting within the guide bushing, and also seated on the upper lat face or' the thrust plate, and centered'on the bushing over the opening die having a throat portion of reduced diameter at its upper end to cause a single contracting flow ot' metal during the extrusion operation7 a tubular punch having e. recessed seat at the top and operating in a guide bushing, a removable punch pin inserted through the tubular punch with its lower end operating beyond the lower face ot' the punch, and having an enlargement et i the upper end retained in the seat of the tubular punch, said punch and punch pin thereby moving in the same direction at the same speed-in all operations.

ln Witness whereof It have hereunto set my hand in the presenceof two Witnesses.

THOMAS PENTLAND CHAMBERS.

Witnesses ALEXANDER CLINE Momu's, EDNA ANNIE ANNIS. l

1n the plete, saidv punch and punch pin moving in the semeg-.sthrust plate and supported by the shoulder?- i eov 

